Papers by Kimmo Kauhaniemi
IEEE Access
In this paper, a direct power control (DPC) approach is proposed for grid-tied AC MG's photovolta... more In this paper, a direct power control (DPC) approach is proposed for grid-tied AC MG's photovoltaic (PV) voltage source inverter (VSI) to regulate directly active and reactive powers by modulating microgrid's (MG) point of common coupling (PCC) voltage. The proposed PCC voltage modulated (PVM) theory-based DPC method (PVMT-DPC) is composed of nonlinear PVM, nonlinear damping, conventional feedforward, and feedback PI controllers. For grid synchronization rather than employing phase-lockedloop (PLL) technology, in this study, direct power calculation of the PCC voltage and current is adopted. Subsequently, at PCC, the computed real and reactive powers are compared with reference powers in order to generate the VSI's control signals using sinusoidal pulse width modulation (SPWM). Because of the absence of the PLL and DPC method adoption, the suggested controller has a faster convergence rate compared to traditional VSI power controllers. Additionally, it displays nearly zero steady-state power oscillations, which assures that MG's power quality is improved significantly. To validate the proposed PVMT-DPC method's performance real-time simulations are conducted via a real-time digital simulator (RTDS) for a variety of cases. The results demonstrate that PV VSI using the suggested PVMT-DPC approach can track the reference power quicker (0.055 s) along with very low steady-state power oscillations, and lower total harmonic distortion (THD) of 1.697% at VSI output current. INDEX TERMS Direct power control, grid-tied, microgrid, PLL, power quality, RTDS, voltage source inverter control.
2019 IEEE PES Innovative Smart Grid Technologies Europe (ISGT-Europe)
In the future, new solutions for active and reactive power control related to the flexibility ser... more In the future, new solutions for active and reactive power control related to the flexibility services from distributed energy resources (DER) will be increasingly needed. One ancillary service which DER could provide is the reactive power flow management between DSO and TSO networks. This research aims to develop a reactive power controller from a preliminary algorithm to a lightweight IED for a wind turbine converter. The purpose of the controller is to maintain the reactive power flow of a medium voltage network within the limit settled by a transmission system operator. In his paper, the controller development stages are presented starting from the preliminary algorithm development by Simscape Power Systems to real hardware and testing it by Controller-Hardware-In-the-Loop simulations. The operation of the controller is investigated in the different development stages of the power network. The outcome is the development suggestions of the real-time simulation platform, as well as the discussion of further improvement possibilities of the controller.
IEEE Access
This paper addresses the black start of medium voltage distribution networks (MV-DNs) by a batter... more This paper addresses the black start of medium voltage distribution networks (MV-DNs) by a battery energy storage system (BESS). The BESS consists of a two-level voltage source inverter interfacing MV-DN which has limited overcurrent capability. On the other hand, MV-DN normally includes several stepup and step-down transformers that are drawing sympathetic inrush current in energizing stage. Therefore, the major difficulty to perform black start by BESS during MV-DN island operation lies in the fact that the inverter has to simultaneous control the network voltage and its output current. This paper presents two control approaches for a BESS in order to control the inrush current during MV-DN black start. The proposed control schemes consist of droop, voltage and current loops in the stationary reference frame. The droop loop is used to generate the voltage reference. An intermediate voltage and inner current loops are designed for output voltage regulation, current reference generation as well as current tracking, respectively. New reference modifiers are included into droop and voltage loops to limit inrush current. The proposed control schemes are experimentally tested for energizing Ingå MV-DN in Finland by 1 MVA BESS, and their performance is compared in terms of inrush current value and voltage quality. The obtained results prove that both methods are able to feed the load with a fixed voltage in the steady-state as well as to limit the transformer inrush current considering the inverter overcurrent limit.
2021 IEEE PES Innovative Smart Grid Technologies Europe (ISGT Europe)
With increasing the diffusion of Power Electronic Converters (PEC) in modern and smart grid syste... more With increasing the diffusion of Power Electronic Converters (PEC) in modern and smart grid systems, the academic and industry R&D researchers rely more and more on the accurate and efficient modelling and simulation of PECs for both hardware and controller design. This paper focuses on the PEC simulation model verification for (time consuming and costly) grid code compliance tests. The simulation model developed based on a full-power laboratory test bench and the waveforms of fault ride through (FRT) tests were compared. The results show that the modelling approach based on averaged inverter captures the dynamic behavior with a good accuracy. Hence, the dynamic behavior of the inverter in FRT tests can be assessed using the simulation approach saving the time and cost required by full power testing.
2018 IEEE Electrical Power and Energy Conference (EPEC), 2018
The restrictions regarding the maximal length of outages especially under major storms has result... more The restrictions regarding the maximal length of outages especially under major storms has resulted in massive underground cabling projects in the network companies in Finland and Sweden. Due to these expensive investments the network fees of many network companies have increased to the extent that the customers have reacted. In both countries, the authorities have announced restrictions to the rate of increase of the network fees. Thus, the network companies are now searching for alternative solutions to underground cabling. This task is here addressed by performing case studies on the network of a rural primary distribution substation area of the Vaasan Sähköverkko distribution company.Technologies surveyed include low voltage (LV) connected battery energy storage (BES), implementation of the 1000 V distribution system in low-power feeder laterals, feeder automation(FA) and both mobile and fixedbackup power generation. The impact of implementing these technologies is then compared...
2021 IEEE PES Innovative Smart Grid Technologies Europe (ISGT Europe), 2021
Partial discharge (PD) diagnosis is an effective tool to track the condition of electrical insula... more Partial discharge (PD) diagnosis is an effective tool to track the condition of electrical insulation in the medium voltage (MV) power components. Machine Learning Algorithms (MLAs) promote automated diagnosis solutions for large scale and reliable maintenance strategy. This paper aims to investigate the performance of two MLAs: Support Vector Machine (SVM) and K-Nearest Neighbors (KNN) for the classification of different types of PD sources. Suitable features are extracted by applying statistical parameters on the coefficients of discrete wavelet transform (DWT) for observing the performance of both MLAs. The performance of the algorithms is evaluated using key performance indicators (KPIs); accuracy, prediction speed and training time. Besides KPIs, a confusion matrix is presented to highlight the accurately classified and misclassified PD signals for the SVM algorithm. Comparative study of both algorithms demonstrates that SVM provides better results as compared to the KNN algorithm. The proposed solution can be valuable for the development of automated classification.
The transition of low voltage (LV) distribution networks towards more intelligent and smart micro... more The transition of low voltage (LV) distribution networks towards more intelligent and smart microgrids is dependent on both technical and behavioral factors, thus forming a socio-technical systems change. Sociotechnical aspects need to be taken into account when developing concepts and models to establish and manage successful niche experiments. This paper presents a new framework to model actor (customer) evolution and engagement in the process of developing smart LV Microgrid distribution networks as socio-technical systems. The framework is based on combining the Multi-level perspective (MLP) and the Strategic niche management (SNM) approach with the Unified Modeling Language (UML) tool. Customer engagement is an essential element in SNM, wherefore understanding their and other actors' different development paths is invaluable to uncover the dynamics of the Microgrid transition in the societal and the technical contexts. The proposed framework could be applied to other key ac...
In the future new options to provide needed technical ancillary services locally and system-wide ... more In the future new options to provide needed technical ancillary services locally and system-wide by distributed energy resources (DER) are needed. One ancillary service which DER could provide is the reactive power management when microgrid is operated in utility grid-connected mode. In this paper different requirements for reactive power flow between distribution and transmission grids were considered in Sundom Smart Grid (SSG) and the measured data from SSG was used for developing a concept for reactive power management. Based on these different requirements "Future Reactive Power Window" was formulated for SSG which was the basis for control scheme formulation. The simulations showed that coordinated reactive power management scheme across different voltage levels by utilizing control of distributed generation could be very beneficial to the voltage support ancillary service.
The popularity of Rogowski sensors is increasing due to their advantages over conventional CTs. C... more The popularity of Rogowski sensors is increasing due to their advantages over conventional CTs. Consequently, network utilities may sometimes end up facing a question whether it would be possible to use line differential protection on a line where the current measurements at the local end are based on CTs, whereas, the remote end measurements are based on current sensors. The main challenge in the use of such a combination in line differential protection applications is that while CTs may saturate, Rogowski sensors do not. Such issues were studied in a hardware-in-the-loop simulation setup. Based on the studies conducted, it appears that the use of mixture of CTs and current sensors for line differential protection applications is a feasible option provided that the CTs are properly dimensioned and that the protection settings are carefully chosen.
Rapid proliferation of underground cables in today's distribution networks need improved faul... more Rapid proliferation of underground cables in today's distribution networks need improved fault monitoring and diagnostic capabilities. Dielectric insulation is the most critical element of underground cables and exposed to various stresses. Cable joints and terminations are always needed and are the most vulnerable locations for insulation defects within the cable feeder. Partial discharge (PD) signals emerging during the progression of insulation faults, travel along the lines and split into connected branches at the T/Y splices. This makes the use of conventional diagnostics solution inappropriate as compared to straight cable section. This paper presents a study on the propagation behaviorof PD signals in a branched joint configuration. Experimental investigations are presented to study the PD propagation across the T/Y-splices. The presented study provides interesting outcomes that can be used for development of an efficient PD monitoring system to watchdog the cable feeder.
2017 IEEE Manchester PowerTech, 2017
Nowadays, different vessel types are mostly operating on diesel generators employing cheap qualit... more Nowadays, different vessel types are mostly operating on diesel generators employing cheap quality fuel, thus causing many types of air pollutions during a stay at the harbour. Thus, electrification by renewable energy based Distributed Generation (DG) and Battery Energy Storage (BES) onboard as well as on shore side are inevitably the best solution to get pollution free energy. In this regard, this paper proposes an innovative design concept of the Harbour Area Smart Grid (HASG) in such a way that it can not only supply the vessels for cold ironing purpose but also supports the hybrid vessels of future technology. The designed HASG is modelled in PSCAD/EMTDC and the simulation case studies have been carried out to validate the performance of the HASG under steady state and transient state.
2021 6th IEEE Workshop on the Electronic Grid (eGRID), 2021
The rapid growth of renewable energy technology enables the concept of microgrid (MG) to be widel... more The rapid growth of renewable energy technology enables the concept of microgrid (MG) to be widely accepted in the power systems. Due to the advantages of the DC distribution system such as easy integration of energy storage and less system loss, DC MG attracts significant attention nowadays. The linear controller such as PI or PID is matured and extensively used by the power electronics industry, but their performance is not optimal as system parameters are changed. In this study, an artificial neural network (ANN) based voltage control strategy is proposed for the DC-DC boost converter. In this paper, the model predictive control (MPC) is used as an expert, which provides the data to train the proposed ANN. As ANN is tuned finely, then it is utilized directly to control the step-up DC converter. The main advantage of the ANN is that the neural network system identification decreases the inaccuracy of the system model even with inaccurate parameters and has less computational burden compared to MPC due to its parallel structure. To validate the performance of the proposed ANN, extensive MATLAB/Simulink simulations are carried out. The simulation results show that the ANN-based control strategy has better performance under different loading conditions comparison to the PI controller. The accuracy of the trained ANN model is about 97%, which makes it suitable to be used for DC microgrid applications.
2020 IEEE PES Innovative Smart Grid Technologies Europe (ISGT-Europe), 2020
Partial discharge (PD) diagnostic is a crucial tool for condition monitoring of power system equi... more Partial discharge (PD) diagnostic is a crucial tool for condition monitoring of power system equipment (e.g. switchgear, cable) in the medium voltage (MV) network, which is degraded by the gradual deterioration of insulation elements, ageing, and various operational and environmental stresses. In the MV network, different types of PD faults are generated from different sources and to know the impact of an individual PD fault on the health of MV equipment, classification plays an important role. This paper aims to provide suitable techniques for classifying PD faults. The data is collected from an experimental investigation of three different types of PD faults from MV switchgear and classified using features extraction, dimensionality reduction and clustering techniques. To identify the best classification technique, dimensionality reduction techniques (principal component analysis and t-distributed stochastic neighbour embedding) are used, and their results are compared using the confusion matrix after applying k-means clustering technique.
IECON 2019 - 45th Annual Conference of the IEEE Industrial Electronics Society, 2019
Due to the large-scale integration of distributed energy resources (DER) new options for the loca... more Due to the large-scale integration of distributed energy resources (DER) new options for the local and system-wide technical ancillary services are needed. Reactive power control is one of such ancillary service provided by DERs. This paper aims to test the performance of a reactive power control scheme developed on a light-weight Intelligent Electronic Device (IED). The IEDs are implemented on a BeagleBoneBlack as well as on an FPGA. The test set-up is implemented by the Controller-Hardware-In-the-Loop platform. The simulation platform is OPAL-RT's eMEGASIM and ePHASORSIM. The results show the performance of the FPGA to be better than BeagleBoneBlack when comparing results of the Sofware-In-the-Loop simulations.
In this paper the functional requirements of the Smart Grid protection are discussed. These requi... more In this paper the functional requirements of the Smart Grid protection are discussed. These requirements arise from specific features of the Smart Grids. For example, Smart Grids include various types of distributed energy resources, which enable more flexible use of grid capacity. With the help of modern ICT technology it is also expected that the power supply reliability is shifted to some higher level. Especially in the distribution system level the changes will be relatively big. The traditional distribution systems are more or less passive while the Smart Grid technology brings in new active elements. The state of the system will be continuously changing and in order to set up suitable protection system some new requirements must be taken into account. The functional requirements of the protection future Smart Grids, especially for the smart distribution networks, are discussed in this paper by analyzing a fixed set of different types of basic protection zones.
Applied Sciences, 2021
Transmission system operators (TSOs) often set requirements to distribution system operators (DSO... more Transmission system operators (TSOs) often set requirements to distribution system operators (DSOs) regarding the exchange of reactive power on the interface between the two parts of the system they operate, typically High Voltage and Medium Voltage. The presence of increasing amounts of Distributed Energy Resources (DERs) at the distribution networks complicates the problem, but provides control opportunities in order to keep the exchange within the prescribed limits. Typical DER control methods, such as constant cosϕ or Q/V functions, cannot adequately address these limits, while power electronics interfaced DERs provide to DSOs reactive power control capabilities for complying more effectively with TSO requirements. This paper proposes an optimisation method to provide power set-points to DERs in order to control the hourly reactive power exchanges with the transmission network. The method is tested via simulations using real data from the distribution substation at the Sundom Sm...
15th International Conference on Developments in Power System Protection (DPSP 2020), 2020
The term digital substation refers to the process of managing operations between intelligent prim... more The term digital substation refers to the process of managing operations between intelligent primary devices and distributed Intelligent Electric Devices (IEDs) interfaced with a highly secure communications network. The process bus is the first part of the interface between the primary instruments (such as the current and voltage transformers and protection devices) and is an important part of digitalization. This paper describes a method for constructing an interface between measurement instruments and protection devices based on the IEC 61850 standard. Two scenarios are considered to examine the performance of the power system protection in a transmission line between two substations. Both a conventional and an IEC 61850-9-2 (sampled values) approach are implemented to feed the measured values to the protection devices. Trip signals are then also sent to the circuit breakers using IEC 61850-8-1 (GOOSE message). Comparing this method with conventional technology, the outcomes for the digital substation are more accurate and reliable thanks to the rapid reaction of protection devices and the speed at which the trip signal is received. The new process bus method has been tested by implementing a hardware-in-the-loop platform, consisting of a real-time simulator (OPAL-RT eMEGAsim), StandAlone Merging Units (SAMUs), and line differential protection.
Technical and economic considerations can both affect the feasibility of microgrids. During the i... more Technical and economic considerations can both affect the feasibility of microgrids. During the implementation of a microgrid, a very significant issue for participation in the energy market is the economic evaluation, which also can improve the efficiency and the advantage of investing in this type of system. This report surveys the literature for information on the economic evaluation, market structures, and business models of microgrids. The structure of energy markets for microgrids is oligopolistic and involves four agents. Also discussed here are the benefits of electricity generation by DG units near the point of consumption, the different ways of selling electricity with Distribution Network Operators (DNOs), and the current barriers and solutions to entry. Keywords; Business model, Market structure, Microgrid
This paper presents a novel Loss of Mains (LoM) protection method based on IEC 61850 General Obje... more This paper presents a novel Loss of Mains (LoM) protection method based on IEC 61850 General Object Oriented Substation Event (GOOSE) protocol. With the increased penetration of distributed generation (DG), the requirements for LoM or anti-islanding protection has become common in the electric utilities. The development of Smart Grids including extensive communication capabilities enables also communication based LoM approaches. Since IEC 61850 standard based systems are the mainstream in the substation communication, expanding this technology deeper in the distribution network provides interesting solution for communication based LoM protection. The standard IEC 61850-7-420 defines logical nodes (LNs) suitable for this purpose but there are not yet available devices applying this part of the standard. Therefore in this research, a light-weight 61850 GOOSE based LoM solution has been developed and demonstrated applying a microcontroller and available open source software. This paper...
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Papers by Kimmo Kauhaniemi